The Internet is a noisy and scary place. When analyzing their network traffic, how can an organization effectively and efficiently sift through all the noise? One method to help with this is to look outward. What do I mean by this? By looking outward, I mean focusing on traffic leaving your enterprise (headed to IP addresses that are external to your network). This works primarily for one reason: Although there may be a great deal of noise on the Internet and a great deal of noise internally, there shouldn't be a cross pollination between those two noisy realms. That cross pollination would be indicative of something anomalous leaving your network (other than the routine/obvious types of outbound traffic that we would expect).
There are some ways to further reduce the noise contained within outbound traffic, and I will blog about those in a future post. The bottom line is that if you can create a jumping off point with very little noise, it's going to be an efficient analytical technique.